Organizers said 10.2 million people registered to take part in the “Great California ShakeOut,” which occurred at 10:19 a.m.

“We have to practice and be prepared,” Los Angeles Mayor Eric Garcetti told KTTV. “Every time you practice it makes muscle memory, it makes memory in your head so that you know instantly and instinctively where to go, what to do and how to protect your life and your loved ones.”

Participants included more than 6 million K-12 students and nearly 2 million people at colleges and universities as well as governments, businesses, faith-based organizations and individuals.

An additional 42 million people have registered for other ShakeOut drills across the United States and its territories as well as from British Columbia to Japan, Italy and New Zealand.